recommendations from the AHA and included 5 minutes of quiet rest, average of three readings 1 minute apart, and appropriate patient positioning.2 However, because of adherence to these recommendations, the use of automated devices, and measurement of BPs in the absence of an observer at some sites, some have questioned the ability to translate SPRINT results into routine clinical practice where measurement of BP is typically less standardized.3 Although numerous hypertension experts have argued that the BP measurement technique in SPRINT makes it an outlier, the SPRINT protocol is much more similar to nearly all prior clinical trials than the technique used in routine clinical practice. Early studies utilized manual BPs7–10 whereas more recent studies have used automated monitors.11–13 Regardless of the type of measurement device, nearly all of the studies that shape our understanding of the relationship between BP and adverse outcomes and guide antihypertensive therapy followed protocols that would be considered adherent to recommendations from the AHA (see Table 1). In addition to a period of quiet rest and multiple readings averaged to represent the clinic BP for that visit, the BP measurement protocols included the use of appropriate cuff size; proper patient positioning including back support, feet flat on floor, and arm supported at heart level; and cuff placed on a bare arm.2 Trained personnel left the room during automated BP measurement at some SPRINT centers. Notably, the AHA guidelines do not comment on the presence or absence of an observer during BP measurement. This is in part due to the fact that prior iterations of the guidelines were published when manual readings predominated because automated devices were just becoming available. The effect of an observer on automated BP readings is unknown. Whereas prior studies have compared manual BPs to unobserved automated BPs,14 to our knowledge, no study has compared BP results for observed versus unobserved measurement techniques using automated devices. Studies have consistently found that nonadherence to specific components of the measurement protocol, such as cuff size, arm position, and rest, leads to higher readings (Table 2, top). Additionally, investigators have compared “routine” clinic BPs to those measured using appropriate protocols and found that routine BPs are typically 5–10 mm Hg higher (Table 2, middle). Unfortunately, the routine and AHA adherent BPs were not measured on the same day or in random order in the majority of these studies. Furthermore, the routine BPs were often obtained retrospectively from the clinic visits at which the patients were referred for ambulatory BP or to a hypertension specialist.15 The type of measurement device, manual versus automated, can also affect BP readings. Given that automated BP measurement in SPRINT may have been unobserved, this last issue has been the subject of much consternation by some, when considering the clinical ramifications of the SPRINT trial results. Regardless, the BP measurement techniques in SPRINTand prior observational studies and randomized trials more closely adhere to AHA Table 1. Method/device, rest, and number of readings from BP protocols for prior large observational studies and clinical trials Study Year Type of Study Method/Device Wait/Rest, min # Readings Framingham23 1970s Observational Manual 5 2 SHEP24 1991 Clinical trial Manual 5 2 MDRD5 1994 Clinical trial Manual 5 3 UKPDS7 1998 Clinical trial Manual 5 3 ALLHAT8 2000 Clinical trial Manual 5 2 HOPE9,10 2001 Clinical trial Manual 15 2 HYVET25 2001 Clinical trial Manual and automated 5 2 AASK6 2002 Clinical trial Manual 5 3 ADVANCE11 2007 Clinical trial Automated/Omron 5 2 CRIC26 2009 Observational study Manual 5 3 ACCORD12 2010 Clinical trial Automated/Omron 5 3 SPS327 2011 Clinical trial Automated/Colin electronic device 15 3 ONTARGET13 2012 Clinical trial Automated/Omron 3 2 CKD-JAC28 2013 Observational study Manual 5 3 SHEP, Systolic Hypertension in the Elderly Program; UKPDS, UK Prospective Diabetes Study; ALLHAT, Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial; HOPE, Heart Outcomes Prevention Evaluation; HYVET, Hypertension in the Very Elderly Trial; ADVANCE, Action in Diabetes and Vascular disease: preterAx and diamicroN-MR Controlled Evaluation; CRIC, Chronic Renal Insufficiency Cohort; ACCORD, Action to Control Cardiovascular Risk in Diabetes; SPS3, Secondary Prevention of Small Subcortical Strokes; ONTARGET, Ongoing Telmisartan Alone and in Combination with Ramipril Global Endpoint Trial; CKDJAC, Chronic Kidney Disease Japan Cohort. 384 Journal of the American Society of Nephrology J Am Soc Nephrol 29: 383–388, 2018 BRIEF REVIEW www.jasn.org recommendations than the technique utilized in routine clinical practice. Ambulatory BP was measured in a subset of SPRINT participants during the treat-to-target phase of the trial. Results from this ancillary study provide new insights on the relationship of BP measured using the SPRINT protocol to ambulatory BP and allow for a comparison with BPs measured in other trials and settings. Twenty-four-hour ambulatory BP was measured during follow-up visits in 897 SPRINT participants at 15 clinical sites.16 Among these participants,